Ukraine moves against insurgents; Russia responds with drills

Relatives mourn as they stand and crouch near the coffin of Volodymyr Rybak, a local councillor from the pro-Western party, reportedly killed by pro-Russia separatists in Slavyansk last week.

Relatives mourn as they stand and crouch near the coffin of...

SLOVYANSK, Ukraine — Russia announced new military exercises Thursday involving ground and air forces near its border with this nation, swiftly responding to a Ukrainian operation to drive pro-Russia insurgents out of occupied buildings in the country's tumultuous east.

Russia's foreign minister warned a day earlier that any attack on Russian citizens or interests in eastern Ukraine would bring a strong response.

Secretary of State John Kerry quickly denounced the Russian actions, and in unusually blunt language warned that unless Moscow took immediate steps to de-escalate the situation, Washington would have no choice but to impose additional sanctions.

“Following today's threatening movement of Russian troops right up to Ukraine's border, let me be clear: If Russia continues in this direction, it will not just be a grave mistake, it will be an expensive mistake,” Kerry said. “The window to change course is closing,”

Accusing Russia of fomenting unrest and separatist sentiment in eastern Ukraine after its annexation of the strategic Crimean Peninsula, Kerry added: “Nobody should doubt Russia's hand in this.”

Animosity between Moscow and Kiev has been high since the ouster of Russia-friendly President Viktor Yanukovych in February after months of protests. Russia contends the government that took over consists of nationalists who aim to suppress the large Russian-speaking population in Ukraine's east.

In March, Russia annexed the Crimean Peninsula after its residents voted to split off from Ukraine. Russian troops backed up local militias that blocked off Ukrainian military bases in the run-up to the referendum.

Ukraine's acting president accused Russia of backing the separatists in the east, and demanded that Moscow stop its intimidation campaign and leave his country alone.

Oleksandr Turchynov said in an address to the nation Thursday that Russia was “coordinating and openly supporting terrorist killers” in eastern Ukraine, where government buildings in at least 10 cities have been seized by pro-Russia gunmen.

Turchynov said Russia must pull back its troops from the Ukrainian border and “stop the constant threats and blackmail.”

His foreign minister, on a visit to Prague, also blasted the Russian decision to start new military maneuvers and said his country would fight any invading troops.

“We will now fight with Russian troops if ... they invade Ukraine. Ukrainian people and the Ukrainian army are ready to do this,” Andriy Deshchytisa said.

With no appetite in the U.S. for a military response, President Barack Obama is largely banking on Putin caving under a cascade of economic sanctions targeting his closest associates. But the success of that strategy also depends on European nations with closer financial ties to Moscow taking similar action, despite their concerns about a boomerang effect on their own economies.

Meanwhile, an American journalist who'd been held by insurgents in the eastern city of Slovyansk was freed Thursday.

Simon Ostrovsky of Vice News said he'd been freed and was heading to Donetsk, the largest city in the region. He did not give details on his seizure or his release.